NASA and Boeing ready for long-delayed, high-stakes Starliner test flight – Spaceflight Now


Boeing’s Starliner spacecraft was lifted atop ULA’s Atlas 5 rocket on May 4 at the Cape Canaveral space station. Credit: United Launch Alliance

Years behind schedule, Boeing’s Starliner crew capsule program is set to make a crucial unmanned test flight to the International Space Station slated for launch Thursday, a resumption of a mission abbreviated 2019 demo that cost the aerospace entrepreneur nearly $600 million.

The Starliner crew capsule is scheduled for liftoff on the Orbital Flight Test 2, or OFT-2, mission from Cape Canaveral at 6:54 p.m. EDT (2254 GMT) Thursday atop a United Launch Alliance Atlas rocket 5.

ULA, Boeing and NASA, which oversees the Starliner commercial crew contract, gave the go-ahead on Tuesday to make final launch preparations. Officials met for a launch readiness review and gave the go-ahead to proceed with the mission.

The review “went very well,” said NASA Commercial Crew Program Manager Steve Stich. “It was short. It was very clean. There’s really no problem with ULA, Boeing or NASA working for the upcoming launch.

The test flight is intended to collect data and prove that Boeing’s Starliner spacecraft is ready to ferry astronauts to and from the space station. It is a redesign of the OFT-1 mission in December 2019, which was interrupted by software glitches that caused the Starliner capsule’s thruster to burn out shortly after launch.

Developed through a public-private partnership, the Starliner spacecraft will give NASA a second human capsule capable of ferrying astronauts to and from the space station, alongside SpaceX’s Dragon spacecraft, which launched with a crew for the first time in May 2020.

Problems with the 2019 flight prevented the Starliner spacecraft from reaching the space station, and Boeing ordered the capsule to re-enter the atmosphere and land in New Mexico two days later.

After rewriting portions of the Starliner software code and subjecting it to more extensive testing, Boeing and NASA continued preparations for the OFT-2 mission – a test flight added to the Starliner program at Boeing’s expense.

The spacecraft was rolled onto the launch pad last August at Cape Canaveral atop its Atlas 5 rocket. But on the morning of the scheduled launch, tests revealed 13 isolation valves stuck in the Starliner propulsion system.

Boeing and NASA have agreed to remove the Starliner from the Atlas 5 rocket and postpone the mission to investigate the valve issue. According to Boeing, tests showed that corrosion inside the valves — caused by a chemical reaction between moisture, nitrogen tetroxide propellant, and the valves’ aluminum casing — caused the components to stick together. interior of spacecraft service module plumbing.

For the OFT-2 mission, engineers improved the seals on the valves to prevent moisture intrusion and added nitrogen purges to keep atmospheric humidity out of the propulsion system. Boeing also swapped out the balky service module from last summer’s launch attempt with an all-new propulsion section, complete with a new set of valves and thrusters.

The company said it plans to change the design of the oxidizer isolation valves – potentially reducing the amount of aluminum in the valve housing – for future Starliner missions, but officials are “confident” in mitigation measures introduced to prevent moisture intrusion prior to launch of OFT-2. .

Boeing took an accounting charge of $595 million to pay for delays, touch-ups and the unplanned OFT-2 mission. NASA’s fixed-price contracts for the Starliner commercial crew program total about $5 billion, an arrangement in which the government and the contractor share the costs of developing the spacecraft.

NASA signed a similar, less expensive contract with SpaceX in 2014 for the development, testing and operations of the human-rated Dragon spacecraft. After encountering its own series of shorter delays, SpaceX launched its first astronaut mission to the space station in 2020.

As Boeing battled Starliner program delays, SpaceX logged seven crew missions on its fleet of reusable Dragon capsules — five for NASA and two for private customers.

Boeing’s contract with NASA covers the unpiloted missions OFT-1 and OFT-2, and a crew flight test that could lift off with a crew of two or three astronauts later this year or early this year. next year, assuming the next demonstration flight is successful. . After the test flights were completed, NASA booked six-crew rotational operational combat with Boeing using the Starliner spacecraft.

Mark Nappi, Boeing’s Starliner program manager, said the delays haven’t zapped the attention of the Starliner team.

“It’s very difficult to build and develop and launch this type of vehicle, so they’re focused on the laser to get it right, and that’s really where they think,” Nappi said, adding that Boeing wants make the program the “safest and safest”. best possible quality.

“When we pitch, we pitch,” Nappi said.

After the launch readiness review is complete, ULA’s ground crew prepares to roll the 172-foot-tall (52.4-meter) Atlas 5 rocket out of the 30-meter Vertical Integration Facility. floors at 10 a.m. EDT (2 p.m. GMT) Wednesday. Two “trackmobile” units will transport the Atlas 5 and the Starliner spacecraft on railroad tracks for the 1,800-foot (550-meter) journey from the VIF to pad 41 at Cape Canaveral.

Teams have stacked the Atlas 5 rocket’s core stage, two strap-on solid rocket boosters, the Centaur upper stage and the Starliner capsule inside the VIF for the past several weeks.

Once on the launch pad, the Atlas 5 and its mobile launch platform will be connected to automatic couplers to load propellants into the rocket. Jet fuel will be pumped into the first stage on Wednesday afternoon, preparing for the start of the launch countdown at 7:34 a.m. EDT (11:34 GMT) on Thursday.

The launch team will load cryogenic thrusters into the Atlas 5 starting early Thursday afternoon, followed by an extended wait. On future astronaut-carrying missions, crew members will board the Starliner spacecraft through the capsule’s hatch during the four-hour countdown break.

The Starliner spacecraft due to launch Thursday as part of Boeing’s OFT-2 mission will not have an astronaut crew on board. An instrumented test dummy named after World War II “Rosie the Riveter” sits in the spacecraft commander’s seat.

An instrumented anthropometric test device, named Rosie, inside the Starliner spacecraft. Credit: Boeing

The Starliner will also carry more than 500 pounds (227 kilograms) of food and other supplies for the space station’s seven-person crew, according to NASA. At the end of the mission, the spacecraft is expected to return to Earth with over 600 pounds (272 kilograms) of cargo.

Friday is a backup launch opportunity, there is a 40% chance of good weather for launch, with more chance of thunderstorms in the launch pad area.

The Starliner team will also assess wind and sea conditions along the Atlas 5 flight path northeast of Cape Canaveral. The capsule could splash into the Atlantic Ocean along the offshore flight path if an emergency triggers a launch shutdown, in which the Starliner’s shutdown engines would propel the ship away from the Atlas 5 rocket.

The capsule launch abort system will be active for the first time on the OFT-2 mission. It operated in “ghost” mode during the launch of OFT-1 in 2019, collecting data for analysis by engineers after the flight.

For a Starliner mission with astronauts on board, abort weather constraints would factor into the decision whether or not to proceed with a launch. During this unpiloted test flight, teams will monitor conditions but will not hold off the launch if they are out of bounds.

If the OFT-2 mission does not lift off Thursday, the next launch opportunity will be Friday at 6:31 p.m. EDT (2231 GMT). Launch times are determined by when the Earth’s rotation brings the launch pad to Cape Canaveral below the space station’s flight path.

After liftoff, the Atlas 5’s two strap-on thrusters and Russian-made mid-engine will generate 1.6 million pounds of thrust to launch the Starliner spacecraft into space. Once their roles are complete, the thrusters and midstage will jettison to fall into the Atlantic, leaving two hydrogen-powered RL10 engines on the Centaur upper stage to propel the Starliner spacecraft on an arcing trajectory just short of the speed required to enter a stable. orbit around the Earth.

The Atlas 5 is programmed to fly on a flatter, less steep trajectory than it flies on typical satellite delivery missions, increasing the possibilities for the Starliner crew capsule to safely escape the rocket. in case of failure.

Once cleared of the Centaur upper stage, the four maneuvers aboard the Starliner will complete the job of bringing the spacecraft into orbit with a burn approximately 31 minutes after liftoff. This burn is the first of several engine ignitions to guide the Starliner spacecraft into automated docking with the space station’s Harmony module.

The orbital link is scheduled for 7:10 p.m. EDT (2310 GMT) Friday, assuming the OFT-2 mission lifts off Thursday.

Space station astronauts will open hatches and enter the Starliner spacecraft on Saturday, remove cargo inside the pressurized crew cabin and perform communications checks in the cockpit.

If all goes according to plan, and assuming good weather on the landing zone, the Starliner would undock from the space station on May 25 and head for reentry, targeting a parachute and airbag assisted landing at White Sands Space Harbor in New Mexico.

Email the author.

Follow Stephen Clark on Twitter: @StephenClark1.


Leave a Reply

Your email address will not be published.